Tubular articles of manufacture and method of making same

ABSTRACT

Heat transfer elements are made by forming a plurality of tubes extending in side-by-side relation with connector means holding adjacent tubes together, cutting and outwardly projecting surface portions of the tubes to form fins, and then severing the connector means to divide the plurality of tubes into individual heat transfer elements.

BACKGROUND OF THE INVENTION

This invention relates to tubular articles of manufacture and the methodof making the same, and, more particularly, to tubular articles ofmanufacture and the method of making the same, wherein, during themanufacture of such tubular articles, and after the initial formingthereof, subsequent manufacturing steps are taken, such as, for example,the forming of external spines or fins thereon in the manufacture of aheat exchanger.

It is a primary object of the present invention to afford a novel methodof making a tubular article of manufacture.

Another object is to afford a novel tubular article of manufacture.

A further object of the present invention is to afford a novel method ofmaking a heat exchanger.

Yet another object is to afford a novel heat exchanger.

Although, in its broader aspects, it is not limited thereto, the presentinvention relates to, and is particularly well adapted for affordingheat exchangers of the general nature of the heat exchangers shown inU.S. Pat. Nos. 3,202,212, 3,229,722, 3,692,105, 3,746,086, 3,850,236,3,866,286, 3,877,517, 3,886,639, 3,901,312 and 3,947,941, wherein spinesor fins are sliced, cut or gouged from walls of tubular members.

Oftentimes, in the manufacture of tubular articles of manufacture,wherein additional manufacturing steps are performed after the initialforming of a tubular member, the performing of the additionalmanufacturing steps poses a substantial problem. For example, if tubularmembers of narrow width are initially formed and subsequentmanufacturing steps, such as, for example, the fin-forming stepsdisclosed in the aforementioned patents, are to be performed, it hasbeen found that it oftentimes is extremely difficult, if not impossibleto securely hold the tubular member against twisting, turning or othermovement during the performance of the additional manufacturing steps.This is particularly true when the height of the tubular member exceedsthe width or base thereof. It is an important object of the presentinvention to enable such difficulties to be overcome in a novel andexpeditious manner.

Another disadvantage of performing such additional manufacturing stepson relatively small, individual tubular members is the time element andexpense involved. Performing such manufacturing steps on individualtubular members, one-by-one, is relatively slow and time consuming and,normally, is undesirable from the standpoint of efficient manufacturing.In the past, in an endeavor to overcome such difficulties anddisadvantages, efforts have been made to simultaneously perform theaforementioned additional manufacturing steps on a plurality of suchindividual tubular members. For example, efforts have been made to clampor otherwise hold a plurality of such individual tubular members inside-by-side relation to each other and to simultaneously perform theadditional manufacturing steps, such as, for example, the forming offins thereon in the manner disclosed in the aforementioned patents. Thishas the advantage, when and if successful, of being more efficient andless time-consuming in the forming of the fins, or the like, suchmanufacturing steps being performed on a plurality of tubular memberssimultaneously, rather than being performed on each individual tubularmember, alone. However, such procedure has several inherentdisadvantages.

For example, for one thing, it has been found to be extremely difficultto hold such a plurality of individual tubular members in fullystationary position relative to each other during a complete fin-formingseries of steps, or the like. When such tubular members are not reliablyheld in properly indexed relation to each other throughout a completeoperation of the aforementioned type, it is impossible to afford tubularmembers of uniform quality.

Another inherent disadvantage, which has come to our intention, is thateven when an operator is successful in fully stationarily holding suchindividual tubular members in indexed relation to each other during acomplete series of such manufacturing steps, the tubular members,themselves, often vary sufficiently in dimension that the end productsafforded by the individual tubular members are not uniform in size. Forexample, it has been found that when an extrusion is made, and,particularly, when a long extrusion is made, because of what is believedto be the contraction or expansion of the parts of the extrusion die byreason of differences in temperature, and the like, the tubular memberproduced at the beginning of the operation oftentimes is of a differentoutside size than that produced later in the operation. As a result,when such a long extrusion is subsequently cut up into shorter lengthsto afford the individual tubular members, which are to be placed inside-by-side relation to each other for the aforementioned simultaneousperformance of manufacturing steps on the plurality of tubular members,the differences in size make it difficult to effectively clamp orotherwise hold the individual tubular members in fully stationaryrelation to each other; and, even when they are successively so held,the differences in size of the side-by-side portions of the tubularmembers causes variations in the results of the operations on thevarious tubular members. For example, when fins are being simultaneouslycut on such side-by-side tubular members across the full lateral widthof such a cluster of tubular members, the differences in size of thedifferent tubular members commonly causes the formation of fins ofdifferent lengths on adjacent ones of tubular members. It is anotherimportant object of the present invention to enable disadvantages of theaforementioned type to be overcome in a novel and expeditious manner.

Another object of the present invention is to enable a plurality oftubular members, which at the completion of the manufacturing operationsthereon will constitute individual, or, at least, groups of a lessernumber of tubular members, to be initially afforded as a single, unitarystructure on which the aforementioned additional manufacturing steps maybe performed simultaneously on all of the members; and to enable suchmembers to be, thereafter, quickly and easily separated from each otherin a novel and expeditious manner.

Another object of the present invention is to afford a novel blank fromwhich individual tubular members may be separated.

Another object of the present invention is to enable such separation tobe quickly and easily effected while affording a blank of theaforementioned type which has sufficient structural strength andintegrity as to insure that the aforementioned additional manufacturingsteps properly may be performed thereon.

Yet another object of the present invention is to afford a novel heatexchanger embodying fins projecting outwardly from opposite lateralsides thereof and a novel rib extending outwardly from at least oneother lateral side, which latter side extends between the firstmentioned lateral sides.

An object ancillary to the foregoing is to enable a ribbed and finnedheat exchanger of the aforementioned type to be produced in a novel andexpeditious manner.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration show preferredembodiments of the present invention and the principles thereof and whatwe now consider to be the best mode in which we have contemplatedapplying these principles. Other embodiments of the present inventionembodying the same or equivalent principles may be used and structuralchanges may be made as desired by those skilled in the art withoutdeparting from the present invention and the purview of the appendedclaims.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a length of tubular member embodying theprinciples of the present invention, and illustrating the principles ofthe method of the present invention;

FIG. 2 is a transverse sectional view taken substantially along the line2--2 in FIG. 1;

FIG. 3 is a fragmentary, longitudinal sectional view taken substantiallyalong the line 3--3 in FIG. 2;

FIG. 4 is a fragmentary, perspective view, similar to FIG. 1, butshowing a novel, individual, finished tubular member, in the form of aheat exchanger, formed from the tubular member blank of FIG. 1;

FIG. 5 is an enlarged, fragmentary sectional view of a portion of thestructure shown in FIG. 2; and

FIG. 6 is a transverse sectional view, similar to FIG. 2, but showing amodified form of the present invention.

DESCRIPTION OF THE EMBODIMENTS SHOWN HEREIN

An elongated, one-piece multi-ported tubular member or tubular memberblank 1 having a plurality of ports 2 extending longitudinallytherethrough in parallel spaced relation to each other, and embodyingthe principles of the present invention, is shown in FIG. 1 toillustrate the presently preferred embodiment of the present invention.The tubular member 1, shown in FIG. 1, is illustrative of the initialform of tubular member that it is desired be first produced in thepractice of the presently preferred method of the present invention. Itis shown as the left, or leading end of a tubular member 3 which isintegral therewith, and which constitutes a heat exchanger blank onwhich fins 4 have been formed, in a subsequent manufacturing process orstep, in accordance with the principles of the preferred method of thepresent invention. However, it is to be remembered that, in its broaderaspects, the present invention is not limited to heat exchangers or tothe method of making the same, as will be discussed in greater detailpresently.

The tubular member 1 is shown in FIG. 1 as embodying four elongatedtubes 5 disposed in uniplanar, parallel, side-by-side relation to eachother. As will be appreciated by those skilled in the art, the tubularmember 1 is shown as embodying four such tubes 5 merely by way ofillustration and not by way of limitation, and it may embody a greateror lesser plurality of tubes without departing from the purview of thepresent invention.

Each of the tubes 5 embodies a side wall 6, which defines the outerperiphery of a respective one of the ports or passageways 2 extendinglongitudinally through the tubular member 1. The tubes 5 are spaced fromeach other, and adjacent ones of the tubes 5 are connected together byconnectors 7 which extend therebetween. The connectors 7 of the tubularmember 1 are formed integrally with the adjacent tubes 5 and extendlongitudinally of the tubular member 1 throughout the entire lengththereof.

The connectors 7 are of such size and construction that they firmly holdthe tubes 5 in assembled relation to each other, while enabling adjacentones of the tubes 5 to be readily separated from each other, as will bediscussed in greater detail hereinafter.

In the preferred form of the tubular member 1 shown in FIG. 1, each ofthe side walls of each of the tubes 5 embodies a top portion 9, a bottomportion 10 and two laterally disposed side portions 11 and 12, with tworibs 13 projecting outwardly from each of the top and bottom portions 9and 10 and extending longitudinally the length thereof in paralleladjacent relation to each other. The ports 2 and the side walls 6, shownin FIGS. 1-5, are rectangular in transverse cross-section. However, inthe broader aspects of the present invention, they could be of othershapes, such as, for example, round.

In the preferred form of the heat exchanger blank 3 manufactured fromthe tubular member 1, the fins 4 project outwardly from the upper wallportions 9 and the lower wall portions 10 of each of the tubular members5, and, in fact, portions of the fins 4 are formed from portions of theaforementioned upper walls 9 and lower walls 10, as will be discussed ingreater detail hereinafter.

Each of the fins 4 projecting outwardly from respective ones of thetubes 5, embodies an elongated base portion 14 having two spines 15projecting outwardly from one longitudinal edge thereof. Each of thefins 4 extends longitudinally across the respective upper and lower wallportions 9 and 10 of the tube 5 from which it projects in substantiallytransverse relation to the length of the respective tube 5, and each ofthe fins 4 embodies one of the aforementioned base portions 14, having alower longitudinal edge portion 16 integral with the respective upper orlower wall portion 9 or 10 of the tube 5 to which it is attached. Eachbase portion 14 projects outwardly from the respective upper or lowerwall portion 9 or 10, preferably in substantially perpendicular relationthereto, with the spines 15 thereon spaced along and projectingoutwardly from the longitudinal edge of the base portion 14 remote fromthe respective tube 5.

The tubular member 1, from which the heat exchanger, shown in thedrawings, is made, may be made of any suitable material, such as, forexample, aluminum, and may be made in any suitable manner, but,preferably, is made by extruding the same.

In making the heat exchanger blank 3, a tubular member such as thetubular member 1, and embodying the ribs 13 extending the full lengththereof may first be made of any suitable material, such as, forexample, aluminum. Thereafter, the fins 4 may be successively formed oneach of the upper portions 9 and lower portions 10 of all of the sidewalls 5 from one end portion of the tubular member 1, such as the endportion A, toward the other end portion, such as the end portion B,thereof, FIG. 1. The fins 4 may each be cut or gouged from the ribs 13and the tubes 5 by means of a suitable cutting tool which first cutsalong lengthwise of the ribs 13 to the right, as viewed in FIG. 3, toform the surface 17 which terminates at its lower end, as viewed in FIG.3, at the base 18 of the ribs 13, the cutting tool then continuing tocut along lengthwise of the wall portions 9 and 10 of the tubes 5underlying the ribs 13, to form the surface 19, FIG. 3. In the practiceof the preferred form of the present invention, the laterally spacedfins 4 are each cut in this manner on all of the tubes 5, and are thenbent outwardly preferably to a position approximately perpendicular tothe plane of the respective wall portions 9 or 10 on which they areformed.

After thus forming the fins 4 along the desired length of the tubularmember 1, such as the length A-C shown in FIG. 1, the tubular member 1may be severed transversely to its length at the point C to therebyafford a heat exchanger blank having fins 4 extending substantially thefull length thereof. As will be appreciated by those skilled in the art,if desired, the formation of the fins 4 may be commenced inwardly of theend portion A of the tubular member 1, and the tubular member 1 may besevered outwardly to the left, as viewed in FIG. 1, of the last formedfin 4 to thereby afford end portions which project outwardly from theoutermost fins 4 to afford connecting members at each end of thefinished heat exchanger. In such last mentioned construction, not shown,the ribs 13 of the tubular member 1, disposed outwardly of theaforementioned outermost fin, preferably are removed by suitable means,such as, for example, grinding to thereby afford a smooth-walled endportion for the completed heated exchanger.

At this stage of the performance of the manufacturing steps beingfollowed to produce a heat exchanger, all of the tubes 5 remainconnected to each other by the connectors 7. Thereafter, those tubes 5which it is desired to separate from each other may be so separated bysevering the connector 7 extending therebetween. Such severing of theconnectors 7 may be accomplished in any suitable manner, such as, forexample, by means of a suitable shearing press or slicing machine, or,if desired, by feeding the member 3, with the fins formed thereon,longitudinally between wedging rollers or pinch rollers disposed betweenthe tubes 5 to be separated, with the rollers forcing the latter tubes 5apart to severe the connectors 7 therebetween by tearing the same.However, we presently prefer to severe the desired connecting members 7by feeding the member 1 longitudinally between slitter wheels or slicingwheels, such as the wheels 20 and 21, FIGS. 1 and 2. As is well known inthe art, in such an operation of a slitter machine, the wheels 20 and 21are disposed on opposite sides of the connectors 7 to be severed, suchas, for example, the connector 7 between the first and second tubes 5 atthe right side of the tubular member 1, shown in FIG. 2, the wheels 20and 21 extending between the adjacent tubes 5 to be separated and beingeffective to slice or shear the connector 7 disposed therebetween duringlongitudinal movement of the tubular member 1 relative to the wheels 20and 21. As will be appreciated by those skilled in the art, such asevering operation may be effected simultaneously on as many of theconnectors 7 as is desired with a single slitter machine.

When a single tube 5 is thus severed from the tubular member 1 in theaforementioned manner, a heat exchanger, such as the heat exchanger 22,shown in FIG. 4, may thus be afforded. The separation of the heatexchanger 22 from the remainder of the tubular member 1 having beenaccomplished after the manufacturing steps, including the formation ofthe fins 4 thereon, were completed, the manufacture of the heatexchanger 22 has been accomplished without the problem of holding asmall tubular member, such as, for example, a single tube 5 of thetubular member 1 in proper position during the aforementionedmanufacturing steps. Also, by forming heat exchangers, such as the heatexchanger 22, in the aforementioned manner, a plurality of such heatexchangers may be simultaneously provided with the fins 4 in a highlyefficient and practical manner.

In the preferred form of the present invention, each of the connectors 7is of the so-called butterfly shape in transverse cross section, havingtwo substantially wedge-shaped, outwardly flaring end portions 23 and 24having outer ends or bases 25 and 26 connected to, and in fact,integrally formed with the side wall portions 11 and 12, respectively,of the adjacent tubes 5, as shown in FIG. 5. The end portions 23 and 24are connected together at their inner ends, midway between the bases 25and 26 by a reduced portion 27, which is of substantially lesserthickness in a vertical direction, as viewed in FIG. 5, than the baseportions 25 and 26.

In the preferred form of the present invention, the thickness of thereduced portion 27 is such that it may be readily severed withoutdistorting the side wall 6 of the adjacent tubes 5. We have found that,to accomplish this, while still maintaining the structural stability ofthe tubular member 1 during the performance of the aforementionedadditional manufacturing steps thereon, the thickness of the portion 27should not be substantially less than one-fifth of the thickness of theside walls 6 of the tubes 5 and not substantially more than one-half ofthat thickness. Thus, when making a heat exchanger, such as the heatexchanger 22, having a wall thickness of not substantially less than0.030" and not substantially more than 0.060" the thickness of theportion 27 should not be substantially less than 0.006" and notsubstantially more than 0.030".

In all instances, where the aforementioned ratios of the thickness ofthe portion 27 to the thickness of the side walls 6 of the tubes 5 aremaintained, it has been found that the adjacent tubes 5 may, in allinstances, be readily separated by shearing or slicing the connectors 7at the portion 27 without causing the aforementioned undesireddistortion of the adjacent tubes 5; and, when the lower ratios of thethickness of the portion 27 to the thickness of the side walls 6 of thetubes 5 are present, such as, for example, the ratio of one to five, theadjacent tubes 5 may be separated from each other by severing theconnectors 7 at the portion 27 thereof by wedging the adjacent tubes 5apart and thus, in effect, tearing the connectors 7 at the portion 27 tothus severe the connection between the adjacent tubes 5. It appears thatthe foregoing is true even with tubular members wherein the side walls 6of the tubes 5 thereof are of substantially greater thickness than theaforementioned 0.060", because, in such instances, the increasedthickness of the side walls 6 of the tubes 5 is such as to effectivelywithstand the distorting forces applied thereto during such severing ofthe thicker connectors 7 therebetween.

It is to be observed that in the preferred form of the invention shownin FIGS. 1-5, the tubular member 1 is formed in such a manner that eachof the tubes 5, even including the outermost tubes 5 at each side of thetubular member 1 embodies the wedge-shaped portion 23 and 24 projectingoutwardly from the side wall portions 11 and 12 thereof, respectively.With this construction, even if all of the tubes 5 are separated fromeach other, at the completion of the manufacturing processes thereon,each is identical in construction, having a wedge-shaped rib afforded bythe aforementioned end portions 23 and 24 of the connectors 7 projectingoutwardly from the left and right sides thereof, respectively, as viewedin FIG. 1.

However, in affording the finished heat exchangers or other tubularmembers, it is not necessary that each of the tubes 5 be severed fromeach other. Heat exchangers embodying various numbers of ports 2extending therethrough may be afforded by severing the appropriatenumbers of tubes 5 in the heat exchanger blank 3, afforded by thecompletely processed tubular member 1, along the appropriate connectors7. Thus, for example, if it were desired to afford a three-port heatexchanger and a one-port heat exchanger from the tubular member 1, shownin FIG. 1, it would merely be necessary to severe the heat exchangerblank 3 along the connector 7 disposed between the two wheels 20 and 21shown in FIG. 2. On the other hand, if it were desired, for example, toafford two two-port heat exchangers, the heat exchanger blank 3 could besevered only along the middle connector 7 shown in FIG. 2.

It is to be observed that, although the connectors 7 are shown herein ashaving a butterfly cross-sectional shape, this is merely by way ofillustration of the preferred embodiment of the present invention andnot by way of limitation. Although, with such construction, certainadvantages are realized, such as, for example, that when the severing ofthe connectors 7 takes place along the reduced portion 27 thereof, wedgeshaped ribs 23 and 24, which are the same in size and shape are affordedon the outer lateral walls of the separated tubes 5, other shapes ofconnectors may be afforded, such as, for example, connectors, not shown,having a rectangular cross-sectional shape, of a suitable, uniformthickness throughout their widths, such as the width of the reducedportions 27, may be afforded without departing from the purview of thebroader aspects of the present invention.

In FIG. 6 a modified form of the present invention in the form of a heatexchanger blank 3a is shown. The heat exchanger blank 3a is similar inmany respects to the heat exchanger blank 3 shown in FIG. 2, and partswhich are identical to parts shown in FIG. 2 are indicated by the samereference numerals and parts which are similar, but have beensubstituted for coreesponding parts are indicated by the same referencenumerals with the suffix "a" added.

In the heat exchanger blank 3a shown in FIG. 6, the outermost wallportions 11a and 12a thereof are flat and do not embody the outwardlyprojecting rib portions 23 and 24 of the heat exchanger blank 3 shown inFIG. 2.

Also, the heat exchanger blank 3a is a two-port tubular member so thatwhen the completed heat exchanger blank 3a is separated along theconnector 7 between the two tubes 5a thereof, two heat exchangers havingone flat lateral wall and one ribbed lateral wall are afforded. Withthis construction, if it if desired to afford heat exchangers havingdifferent opposite lateral surfaces, and, therefore, different air flowcharacteristics across the opposite lateral surfaces, this may bereadily accomplished by forming the original tubular membe-in the formof a two-port unit having the construction of the tubular member 1a,and, after completing the additional manufacturing steps thereon,severing the two tubes 5a from each other. Following such a procedure,enables individual heat exchangers of relatively narrow width to havethe aforementioned manufacturing steps performed thereon while they areeffectively connected to other stabilizing structure so as to overcomethe aforementioned difficulties of holding tubular members of suchnarrow widths against twisting and turning, and enabling themanufacturing steps to be simultaneously performed on a plurality oftubes so as to conserve man-power and manufacturing time.

As will be appreciated by those skilled in the art, if it is desired tomerely afford occasional heat exchangers having the one flat outer sideof the heat exchangers afforded by the heat exchanger blank 1a, tubularmembers, not shown, having more than two ports therethrough, such as,for example, the tubular member 1 shown in FIG. 1, may be affordedwherein only the outside tubes 5 thereof have the flat outer walls, suchas the walls 11a and 12a shown in FIG. 6, with the intermediate tubesconnected together in the same manner as the intermediate tubes shown inFIG. 1. With such construction, if each of the tubes 5 are separatedfrom each other after completion of the manufacturing processes thereon,only the two outermost heat exchangers will have the one flat wall andthe remainder will have the ribbed construction, on each of the outerlateral walls, of the heat exchanger 22 shown in FIG. 4. Also, ofcourse, by severing the heat exchanger blank afforded by a tubularmember of the last mentioned type, which has more than two ports 2therein at the appropriate place, multiple-port heat exchangers having aflat side wall portion at one lateral side thereof and a ribbed sidewall portion at the other lateral side thereof may be afforded.

As will be appreciated by those skilled in the art, although the presentinvention is particularly well adapted for affording finned heatexchangers, and the like, the present invention, in its broader aspects,is not limited thereto. The method of the present invention, in itsbroader aspects, may be practiced to afford tubular members, in and ofthemselves. For example, a multi-port tubular member, such as thetubular member 1, may be originally formed and with or withoutadditional manufacturing steps being performed thereon, it can beseparated, in the aforementioned manner, into individual tubes orcombinations of various numbers of tubes.

From the foregoing, it will be seen that the present invention affords anovel method of making a tubular article of manufacture.

Also, it will be seen that the present invention, affords a novel methodof making a heat exchanger.

In addition, it will be seen that the present invention affords a noveltubular article of manufacture as well as a novel heat exchanger.

Thus, while we have illustrated and described the preferred embodimentsof our invention, it is to be understood that these are capable ofvariation and modification, and we therefore do not wish to be limitedto the precise details set forth, but desire to avail ourselves of suchchanges and alterations as fall within the purview of the followingclaims.

We claim:
 1. The method of making a tubular article of manufacturecomprisinga. forming an elongated tubular member comprising(1) aplurality of elongated tubes extending longitudinally of said tubularmember and disposed in side-by-side relation to each other, and (2)connector means extending between adjacent ones of said tubes forholding said tubes together to form a single unitary structure, and b.thereafter forming fins on the exteriors of said tubes, and c.thereafter separating at least certain of said tubes from each otheralong said connector means extending therebetween.
 2. The method definedin claim 1, and in whicha. said fins are formed by cutting the same fromthe exteriors of said tubes.
 3. The method defined in claim 2, and inwhicha. said tubular member is formed by extruding the same.
 4. Themethod of making heat transfer elements, comprisinga. forming anelongated tubular member having(1) a plurality of tubes extendinglongitudinally of said member in side-by-side relation to each other,and (2) connector means extending between adjacent ones of said tubesand holding them together, b. successively, from one end portion of saidtubular member toward the other end portion thereof,(1) cutting finsfrom said tubes, and (2) turning said fins outwardly into outwardlyprojecting relation to said tubes, and c. dividing said tubular memberinto said heat transfer elements by severing said connector meansbetween at least certain ones of said adjacent ones of said tubes toseparate the latter from each other.
 5. The method defined in claim 4,and in which1. said severing of said connector means is effected byshearing the latter.
 6. The method defined in claim 4, and in whicha.said severing of said connector means is effected by wedging apart saidcertain ones of said tubes connected thereby in said tubular member.